The present invention relates to a semiconductor memory device, and more particularly to a semiconductor memory device having a data masking function in a write operation and a data masking method of the same.
A semiconductor memory device typically provides a data mask function, where the operation of a write driver is controlled using an externally input data mask signal for masking data in a write operation.
When data is inputted from outside the semiconductor memory device, the data passes through a data input path and is then transferred to the write driver via a global input/output line. The data mask signal passes through a data mask input path which is identical to the path of the data input path, and is then transferred to the write driver via a global input/output line.
The data and the data mask signal inputted into the write driver race to the write driver, i.e., the time at which the write driver receives the data and the data mask signal determines whether the data is masked or not.
However, even though the data input path and the data mask input path are identical, it is possible that the data and data mask signal will not inputted into the write driver at the same time as intended, which is caused by, for example, certain processes or a change in the external environment.
Consequently, if the data mask signal is inputted into the write driver prior to the input of the data, data that should have been protected may in fact not be protected, thereby resulting in a poor data mask function.